b18c boosted or b18a boosted?

alright so i have my turbo kit almost complete. currently thinking about buying a benson sleeved 84mm b18c block. can be had for about 900 used with cp pistons no rods. i have a pr3 and p72 head. would i be better to go that route or build my b18a1? i have heard a lot about dohc vtec being harder to tune. is this true? thanks forthe help.it wil be going in a 90 ef. pwo or p28?